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To determine the intracellular behavior of p62, a marker of selective autophagy, in oral potentially malignant disorders (OPMDs). This retrospective study includes 70 patients who underwent biopsy or surgical resection and were definitively diagnosed with OPMDs. Immunohistochemical staining for p62, XPO1, p53, and ki67 was performed on all samples and positive cell occupancy was calculated. We statistically investigated the correlation between protein expression in OPMDs and the association between malignant transformation, clinicopathological characteristics, and occupancy. ki67 expression was negatively correlated with p62 expression in the nucleus (p < 0.01) and positively correlated with p62 expression in the cytoplasm (p < 0.01). For malignant transformation, the expression of p62 in the nucleus (p = 0.03) was significantly lower in malignant transformation cases, whereas the expression of p62 in the cytoplasm (p = 0.03) and the aggregation expression (p < 0.01) were significantly higher. Our results suggest that the function of p62 is altered by its subcellular localization. In addition, defects in selective autophagy occur in cases of malignant transformation, suggesting that p62 is a potential biomarker of the risk of malignant transformation of OPMDs.
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Six mutations in the salt-inducible kinase 1 (SIK1) have been identified in developmental and epileptic encephalopathy (DEE-30) patients, and two of the mutations are nonsense mutations that truncate the C-terminal region of SIK1. In a previous study, we generated SIK1 mutant (SIK1-MT) mice recapitulating the C-terminal truncated mutations using CRISPR/Cas9-mediated genome editing and found an increase in excitatory synaptic transmission and enhancement of neural excitability in neocortical neurons in SIK1-MT mice. NMDA was injected into SIK1-MT males to induce epileptic seizures in the mice. The severity of the NMDA-induced seizures was estimated by the latency and the number of tail flickering and hyperflexion. Activated brain regions were evaluated by immunohistochemistry against c-fos, Iba1, and GFAP. As another epilepsy model, pentylenetetrazol was injected into the adult SIK1 mutant mice. Seizure susceptibility induced by both NMDA and PTZ was enhanced in SIK1-MT mice. Brain regions including the thalamus and hypothalamus were strongly activated in NMDA-induced seizures. The epilepsy-associated mutation of SIK1 canceled the pharmacological effects of the ACTH treatment on NMDA-induced seizures. These results suggest that SIK1 may be involved in the neuropathological mechanisms of NMDA-induced spasms and the pharmacological mechanism of ACTH treatment.
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Epilepsia , Proteínas Serina-Treonina Quinases , Hormônio Adrenocorticotrópico/genética , Animais , Eletroencefalografia , Epilepsia/induzido quimicamente , Epilepsia/tratamento farmacológico , Epilepsia/genética , Masculino , Camundongos , Mutação , N-Metilaspartato/genética , Proteínas Serina-Treonina Quinases/genética , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológico , Convulsões/genética , Espasmo/tratamento farmacológico , Espasmo/genéticaRESUMO
PURPOSE: Detecting deep vein thrombosis (DVT) is necessary to reduce the morbidity of venous thromboembolism, and platelet-lymphocyte ratio (PLR) is a novel marker for predicting DVT. This study aimed to investigate the association between preoperative PLR and risk of developing DVT in patients receiving surgical treatment of oral cancer. PATIENTS AND METHODS: We designed a retrospective cohort study, and the source of study sample was patients with oral cancer and who underwent surgery between 2015 and 2019. Patients were excluded if they did not undergo surgical treatment and had preoperative DVT and history of hypercoagulable disorders. The primary predictor variable was PLR. We calculated the receiver operating characteristic curve and area under the curve to determine the best-defined risk groups. The best cutoff value for PLR was 187.4 (area under the curve, 0.772; sensitivity, 75.0%; specificity, 74.2%; P = .002). The primary outcome variable was DVT, and the other variables were patient characteristics, blood examination data, and therapeutic data. A logistic regression analysis was used to adjust the effects of potential confounders. RESULTS: A total of 101 patients were included in this study, and DVT was observed in 12 (11.9%) patients. Free flap reconstructive surgery was performed in 8 of the 12 (66.7%) patients in the DVT group. Statistical analyses showed that DVT was significantly associated with PLR (≤187.4 vs >187.4; P = .001). Logistic multivariate analysis of the preoperative parameters identified the following 2 independent predictive factors for DVT: PLR (≤187.4 vs >187.4) (odds ratio, 13.735; 95% confidence interval, 2.950 to 63.944; P = .001) and free flap reconstructive surgery (odds ratio, 6.584; 95% confidence interval, 1.504 to 28.822; P = .012). CONCLUSIONS: High PLR (>187.4) and free flap reconstructive surgery, considered as preoperative predictive factors, were associated with DVT.
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Neoplasias Bucais , Tromboembolia Venosa , Trombose Venosa , Humanos , Linfócitos , Neoplasias Bucais/cirurgia , Estudos Retrospectivos , Trombose Venosa/etiologiaRESUMO
The p62 (also named sequestosome1/SQSTM1) is multidomain and multifunctional protein associated with several physiological and pathological conditions. A number of studies evidenced an involvement of p62 on the disruptive bone scenarios due to its participation in the inflammatory/osteoclastogenic pathways. However, so far, information regarding the function of p62 in the fine-tuned processes underpinning the bone physiology are not well-defined and are sometime discordant. We, previously, demonstrated that the intramuscular administration of a plasmid coding for p62 was able to contrast bone loss in a mouse model of osteopenia. Here, in vitro findings showed that the p62 overexpression in murine osteoblasts precursors enhanced their maturation while the p62 depletion by a specific siRNA, decreased osteoblasts differentiation. Consistently, the activity of osteoblasts from p62-/- mice was reduced compared with wild-type. Also, morphometric analyses of bone from p62 knockout mice revealed a pathological phenotype characterized by a lower turnover that could be explained by the poor Runx2 protein synthesis in absence of p62. Furthermore, we demonstrated that the parathyroid hormone (PTH) regulates p62 expression and that the osteogenic effects of this hormone were totally abrogated in osteoblasts from p62-deficient mice. Therefore, these findings, for the first time, highlight the important role of p62 both for the basal and for PTH-stimulated bone remodeling.
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Remodelação Óssea/fisiologia , Osso e Ossos/metabolismo , Osteogênese/fisiologia , Hormônio Paratireóideo/metabolismo , Proteína Sequestossoma-1/metabolismo , Animais , Doenças Ósseas Metabólicas/metabolismo , Reabsorção Óssea/metabolismo , Reabsorção Óssea/fisiopatologia , Osso e Ossos/fisiologia , Diferenciação Celular/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Humanos , Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Osteoblastos/metabolismo , Osteoblastos/fisiologia , Osteoclastos/metabolismo , Osteoclastos/fisiologiaRESUMO
Autophagy plays an essential role in intracellular degradation and maintenance of cellular homeostasis in all cells, including neurons. Although a recent study reported a copy number variation of Ulk2, a gene essential for initiating autophagy, associated with a case of schizophrenia (SZ), it remains to be studied whether Ulk2 dysfunction could underlie the pathophysiology of the disease. Here we show that Ulk2 heterozygous (Ulk2+/-) mice have upregulated expression of sequestosome-1/p62, an autophagy-associated stress response protein, predominantly in pyramidal neurons of the prefrontal cortex (PFC), and exhibit behavioral deficits associated with the PFC functions, including attenuated sensorimotor gating and impaired cognition. Ulk2+/- neurons showed imbalanced excitatory-inhibitory neurotransmission, due in part to selective down-modulation of gamma-aminobutyric acid (GABA)A receptor surface expression in pyramidal neurons. Genetically reducing p62 gene dosage or suppressing p62 protein levels with an autophagy-inducing agent restored the GABAA receptor surface expression and rescued the behavioral deficits in Ulk2+/- mice. Moreover, expressing a short peptide that specifically interferes with the interaction of p62 and GABAA receptor-associated protein, a protein that regulates endocytic trafficking of GABAA receptors, also restored the GABAA receptor surface expression and rescued the behavioral deficits in Ulk2+/- mice. Thus, the current study reveals a novel mechanism linking deregulated autophagy to functional disturbances of the nervous system relevant to SZ, through regulation of GABAA receptor surface presentation in pyramidal neurons.
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Autofagia/genética , Proteínas Serina-Treonina Quinases/genética , Esquizofrenia/genética , Proteína Sequestossoma-1/genética , Animais , Variações do Número de Cópias de DNA/genética , Regulação da Expressão Gênica/genética , Humanos , Camundongos , Peptídeos/genética , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/patologia , Transporte Proteico/genética , Células Piramidais/metabolismo , Células Piramidais/patologia , Receptores de GABA-A/genética , Esquizofrenia/fisiopatologia , Transmissão Sináptica/genéticaRESUMO
Gene knock-in using the CRISPR/Cas9 system can be achieved in a specific population of neurons in the mouse brain, by using in utero electroporation to introduce DNA fragments into neural progenitor cells. Using this strategy, we previously knocked-in the EGFP coding sequence into the N-terminal region of the ß-actin gene specifically in the pyramidal neurons in layer 2/3 of the somatosensory cortex. However, the knock-in efficiency was less than 2% of the transfected neurons. In this study, we sought to improve the knock-in efficiency using this system. First, we varied the length of the homology arms of the ß-actin donor template DNA, and found that the knock-in efficiency was increased to â¼14% by extending the length of the 5' and 3' homology arms to 1.6 kb and 2.0 kb, respectively. We then tested the effect of the DNA repair protein RAD51 and the knock-in efficiency was increased up to 2.5-fold when co-transfecting with two different ß-actin and a camk2a targeting EGFP knock-in modules. The RAD51 overexpression did not alter the migration of developing neurons, density or morphology of the dendritic spines compared to those in neurons not transfected with RAD51. RAD51 expression will be useful for increasing the knock-in efficiency in neurons in vivo by CRISPR/Cas9-mediated homology directed repair (HDR).
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Encéfalo/citologia , Sistemas CRISPR-Cas/genética , Reparo do DNA por Junção de Extremidades , Técnicas de Introdução de Genes , Neurônios/metabolismo , Actinas/metabolismo , Animais , Sequência de Bases , Proteínas de Fluorescência Verde/metabolismo , Camundongos Endogâmicos ICR , Células Piramidais/metabolismo , RNA Guia de Cinetoplastídeos/metabolismo , Rad51 RecombinaseRESUMO
CRISPR/Cas9-mediated gene knock-in in in vivo neurons using in utero electroporation is a powerful technique, but the knock-in efficiency is generally low. We previously demonstrated that co-transfection with RAD51, a key molecule of the initial step of homology-directed repair (HDR), expression vector increased EGFP knock-in efficiency in the ß-actin site up to 2.5-fold in the pyramidal neurons in layer 2/3 of the somatosensory cortex of mouse brain. To further improve the efficiency, we examined the effect of inhibition of DNA ligase IV (LIG4) that is an essential molecule for non-homologous end joining (NHEJ). Co-transfection with small hairpin RNA for LIG4 (shlig4) expression vector increased the EGFP knock-in efficiency in the ß-actin site up to 3.6-fold compared to the condition without shlig4. RAD51 and shlig4 expression vector co-transfection further increased the knock-in efficiency up to 4.7-fold of the control condition. These results suggest that the inhibition of LIG4 is more effective than RAD51 overexpression, and it enhances the effect of RAD51 overexpression on HDR-mediated gene knock-in in vivo neurons.
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Encéfalo/metabolismo , Sistemas CRISPR-Cas , DNA Ligase Dependente de ATP/antagonistas & inibidores , Técnicas de Introdução de Genes/métodos , Neurônios/metabolismo , Animais , Células Cultivadas , DNA Ligase Dependente de ATP/genética , Eletroporação , Proteínas de Fluorescência Verde/genética , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/citologia , Neurônios/fisiologia , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismo , Reparo de DNA por Recombinação , TransfecçãoRESUMO
This article was originally published under standard licence, but has now been made available under a [CC BY 4.0] license. The PDF and HTML versions of the paper have been modified accordingly.
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Calcium/calmodulin-dependent serine protein kinase (CASK) is a membrane-associated guanylate kinase (MAGUK) protein that is associated with neurodevelopmental disorders. CASK is thought to have both pre- and postsynaptic functions, but the mechanism and consequences of its functions in the brain have yet to be elucidated, because homozygous CASK-knockout (CASK-KO) mice die before brain maturation. Taking advantage of the X-chromosome inactivation (XCI) mechanism, here we examined the synaptic functions of CASK-KO neurons in acute brain slices of heterozygous CASK-KO female mice. We also analyzed CASK-knockdown (KD) neurons in acute brain slices generated by in utero electroporation. Both CASK-KO and CASK-KD neurons showed a disruption of the excitatory and inhibitory (E/I) balance. We further found that the expression level of the N-methyl-D-aspartate receptor subunit GluN2B was decreased in CASK-KD neurons and that overexpressing GluN2B rescued the disrupted E/I balance in CASK-KD neurons. These results suggest that the down-regulation of GluN2B may be involved in the mechanism of the disruption of synaptic E/I balance in CASK-deficient neurons.
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Guanilato Quinases/deficiência , Guanilato Quinases/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Encéfalo/metabolismo , Cálcio/metabolismo , Calmodulina/metabolismo , Feminino , Guanilato Quinases/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/metabolismo , Proteínas Quinases/metabolismo , Sinapses/metabolismo , Transmissão Sináptica/fisiologiaRESUMO
With advancing age have been observed bone and bone marrow phenotypic alterations due to the impaired bone tissue homeostatic features, involving bone remodeling, and bone marrow niche ontogeny. The complex "inflamm-aging" pathological scenario that culminates with osteopenia and mesenchymal/stromal and hematopoietic stem cell commitment breakdown, is controlled by cellular and molecular intramural components comprising adapter proteins such as the sequestosome 1 (p62/SQSTM1). p62, a "multiway function" protein, has been reported as an effective anti-inflammatory, bone-building factor. In this view, we considered for the first time the involvement of p62 in aging bone and bone marrow of 1 year and 2 years p62-/- mice. Interestingly, p62 deficiency provoked accelerated osteopenia and impaired niche operational activities within the bone marrow. The above findings unearthed the importance of p62 in mesenchymal stem cell maintenance/differentiation schedule in old animals and provide, at least in part, a mechanistic scenario of p62 action.
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Streptococcus pneumoniae is the most common causative agent of community-acquired pneumonia and can penetrate epithelial barriers to enter the bloodstream and brain. We investigated intracellular fates of S. pneumoniae and found that the pathogen is entrapped by selective autophagy in pneumolysin- and ubiquitin-p62-LC3 cargo-dependent manners. Importantly, following induction of autophagy, Rab41 was relocated from the Golgi apparatus to S. pneumoniae-containing autophagic vesicles (PcAV), which were only formed in the presence of Rab41-positive intact Golgi apparatuses. Moreover, subsequent localization and regulation of K48- and K63-linked polyubiquitin chains in and on PcAV were clearly distinguishable from each other. Finally, we found that E3 ligase Nedd4-1 was recruited to PcAV and played a pivotal role in K63-linked polyubiquitin chain (K63Ub) generation on PcAV, promotion of PcAV formation, and elimination of intracellular S. pneumoniae. These findings suggest that Nedd4-1-mediated K63Ub deposition on PcAV acts as a scaffold for PcAV biogenesis and efficient elimination of host cell-invaded pneumococci.
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Autofagia , Células Epiteliais/imunologia , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Poliubiquitina/metabolismo , Streptococcus pneumoniae/imunologia , Estreptolisinas/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Linhagem Celular , Células Epiteliais/microbiologia , Humanos , UbiquitinaçãoRESUMO
PURPOSE: Lymph node ratio (LNR), defined as the ratio of positive resected lymph nodes (LNs) to the total number of resected LNs, predicts survival for some solid tumors. This study investigated the value of LNR in the prognosis and postsurgical management of oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: The authors designed a retrospective cohort study and enrolled a sample of patients who were diagnosed with OSCC and treated by neck dissection. The predictor was LNR and the outcome variable was overall survival (OS). Other variables were dissection type, postsurgical management, number of positive LNs, pN stage, nodal disease area, extracapsular spread, perineural invasion, vascular invasion, and lymph duct invasion. Differences in OS rate were analyzed by log-rank test. A Cox proportional hazards model was used to adjust for the effects of potential confounders. Differences with a P value less than .05 were considered statistically significant. RESULTS: In 95 patients with OSCC, the LNR cutoff value for predicting overall OS was 0.04 (area under the curve, 0.705; P = .010). There was a significant difference in OS when patients were stratified according to LNR (rate for low LNR, 90.5%; rate for high LNR, 68.8%; P = .014). Univariate analyses showed close correlations between OS and LNR, pT stage, number of positive LNs, and nodal disease area (levels IV and V). Cox multivariate analysis identified LNR (hazard ratio [HR] = 2.889; 95% confidence interval [CI], 1.032-8.087; P = .043) and area of nodal disease (levels IV and V; HR = 5.149; 95% CI, 1.428-18.566; P = .012) as independent predictive factors for OS. OS differed significantly between the high-LNR and low-LNR groups treated by surgery alone (P = .027). CONCLUSIONS: As a predictive factor, high LNR (>0.04) was associated with decreased survival, and intensive adjuvant therapy could improve the prognosis for patients with high LNR.
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Carcinoma de Células Escamosas , Metástase Linfática , Neoplasias Bucais , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/cirurgia , Humanos , Excisão de Linfonodo , Razão entre Linfonodos , Linfonodos , Neoplasias Bucais/diagnóstico , Neoplasias Bucais/cirurgia , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by a selective loss of motor neurons in the brain and spinal cord. Multiple toxicity pathways, such as oxidative stress, misfolded protein accumulation, and dysfunctional autophagy, are implicated in the pathogenesis of ALS. However, the molecular basis of the interplay between such multiple factors in vivo remains unclear. Here, we report that two independent ALS-linked autophagy-associated gene products; SQSTM1/p62 and ALS2/alsin, but not antioxidant-related factor; NFE2L2/Nrf2, are implicated in the pathogenesis in mutant SOD1 transgenic ALS models. We generated SOD1H46R mice either on a Nfe2l2-null, Sqstm1-null, or Sqstm1/Als2-double null background. Loss of SQSTM1 but not NFE2L2 exacerbated disease symptoms. A simultaneous inactivation of SQSTM1 and ALS2 further accelerated the onset of disease. Biochemical analyses revealed that loss of SQSTM1 increased the level of insoluble SOD1 at the intermediate stage of the disease, whereas no further elevation occurred at the end-stage. Notably, absence of SQSTM1 rather suppressed the mutant SOD1-dependent accumulation of insoluble polyubiquitinated proteins, while ALS2 loss enhanced it. Histopathological examinations demonstrated that loss of SQSTM1 accelerated motor neuron degeneration with accompanying the preferential accumulation of ubiquitin-positive aggregates in spinal neurons. Since SQSTM1 loss is more detrimental to SOD1H46R mice than lack of ALS2, the selective accumulation of such aggregates in neurons might be more insulting than the biochemically-detectable insoluble proteins. Collectively, two ALS-linked factors, SQSTM1 and ALS2, have distinct but additive protective roles against mutant SOD1-mediated toxicity by modulating neuronal proteostasis possibly through the autophagy-endolysosomal system.
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Esclerose Lateral Amiotrófica/metabolismo , Encéfalo/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Neurônios Motores/metabolismo , Proteína Sequestossoma-1/metabolismo , Superóxido Dismutase-1/metabolismo , Superóxido Dismutase/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Autofagia/genética , Encéfalo/patologia , Endossomos/genética , Endossomos/metabolismo , Endossomos/patologia , Fatores de Troca do Nucleotídeo Guanina/genética , Humanos , Lisossomos/genética , Lisossomos/metabolismo , Lisossomos/fisiologia , Camundongos , Camundongos Transgênicos , Neurônios Motores/patologia , Mutação de Sentido Incorreto , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Proteína Sequestossoma-1/genética , Superóxido Dismutase/genética , Superóxido Dismutase-1/genéticaRESUMO
Peroxiredoxin (PRDX)1 is an antioxidant that detoxifies hydrogen peroxide and peroxinitrite. Compared with wild-type (WT) mice, Prdx1-deficient (Prdx1-/-) mice showed increased susceptibility to Mycobacterium tuberculosis and lower levels of IFN-γ and IFN-γ-producing CD4+ T cells in the lungs after M. tuberculosis infection. IL-12 production, c-Rel induction, and p38 MAPK activation levels were lower in Prdx1-/- than in WT bone marrow-derived macrophages (BMDMs). IFN-γ-activated Prdx1-/- BMDMs did not kill M. tubercuosis effectively. NO production levels were lower, and arginase activity and arginase 1 (Arg1) expression levels were higher, in IFN-γ-activated Prdx1-/- than in WT BMDMs after M. tuberculosis infection. An arginase inhibitor, Nω-hydroxy-nor-arginine, restored antimicrobial activity and NO production in IFN-γ-activated Prdx1-/- BMDMs after M. tuberculosis infection. These results suggest that PRDX1 contributes to host defenses against M. tuberculosis PRDX1 positively regulates IL-12 production by inducing c-Rel and activating p38 MAPK, and it positively regulates NO production by suppressing Arg1 expression in macrophages infected with M. tuberculosis.
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Mycobacterium tuberculosis/imunologia , Peroxirredoxinas/imunologia , Animais , Interleucina-12/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/biossíntese , Peroxirredoxinas/deficiênciaRESUMO
Huntington's disease (HD) is a dominantly inherited genetic disease caused by mutant huntingtin (htt) protein with expanded polyglutamine (polyQ) tracts. A neuropathological hallmark of HD is the presence of neuronal inclusions of mutant htt. p62 is an important regulatory protein in selective autophagy, a process by which aggregated proteins are degraded, and it is associated with several neurodegenerative disorders including HD. Here, we investigated the effect of p62 depletion in three HD model mice: R6/2, HD190QG and HD120QG mice. We found that loss of p62 in these models led to longer life spans and reduced nuclear inclusions, although cytoplasmic inclusions increased with polyQ length. In mouse embryonic fibroblasts (MEFs) with or without p62, mutant htt with a nuclear localization signal (NLS) showed no difference in nuclear inclusion between the two MEF types. In the case of mutant htt without NLS, however, p62 depletion increased cytoplasmic inclusions. Furthermore, to examine the effect of impaired autophagy in HD model mice, we crossed R6/2 mice with Atg5 conditional knockout mice. These mice also showed decreased nuclear inclusions and increased cytoplasmic inclusions, similar to HD mice lacking p62. These data suggest that the genetic ablation of p62 in HD model mice enhances cytoplasmic inclusion formation by interrupting autophagic clearance of polyQ inclusions. This reduces polyQ nuclear influx and paradoxically ameliorates disease phenotypes by decreasing toxic nuclear inclusions.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Doença de Huntington/genética , Corpos de Inclusão Intranuclear/genética , Fenótipo , Animais , Autofagia , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Modelos Animais de Doenças , Feminino , Hipocampo/metabolismo , Hipocampo/patologia , Doença de Huntington/mortalidade , Doença de Huntington/patologia , Espaço Intracelular/metabolismo , Longevidade/genética , Camundongos , Camundongos Knockout , Peptídeos/genética , ProteóliseRESUMO
Accumulating evidence indicates that the capacity to integrate information in the brain is a prerequisite for consciousness. Integrated Information Theory (IIT) of consciousness provides a mathematical approach to quantifying the information integrated in a system, called integrated information, Φ. Integrated information is defined theoretically as the amount of information a system generates as a whole, above and beyond the amount of information its parts independently generate. IIT predicts that the amount of integrated information in the brain should reflect levels of consciousness. Empirical evaluation of this theory requires computing integrated information from neural data acquired from experiments, although difficulties with using the original measure Φ precludes such computations. Although some practical measures have been previously proposed, we found that these measures fail to satisfy the theoretical requirements as a measure of integrated information. Measures of integrated information should satisfy the lower and upper bounds as follows: The lower bound of integrated information should be 0 and is equal to 0 when the system does not generate information (no information) or when the system comprises independent parts (no integration). The upper bound of integrated information is the amount of information generated by the whole system. Here we derive the novel practical measure Φ* by introducing a concept of mismatched decoding developed from information theory. We show that Φ* is properly bounded from below and above, as required, as a measure of integrated information. We derive the analytical expression of Φ* under the Gaussian assumption, which makes it readily applicable to experimental data. Our novel measure Φ* can generally be used as a measure of integrated information in research on consciousness, and also as a tool for network analysis on diverse areas of biology.
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Estado de Consciência/fisiologia , Teoria da Informação , Modelos Neurológicos , Animais , Córtex Cerebral/fisiologia , Biologia Computacional , Eletrocorticografia , Macaca , Distribuição NormalRESUMO
What aspects of neuronal activity distinguish the conscious from the unconscious brain? This has been a subject of intense interest and debate since the early days of neurophysiology. However, as any practicing anesthesiologist can attest, it is currently not possible to reliably distinguish a conscious state from an unconscious one on the basis of brain activity. Here we approach this problem from the perspective of dynamical systems theory. We argue that the brain, as a dynamical system, is self-regulated at the boundary between stable and unstable regimes, allowing it in particular to maintain high susceptibility to stimuli. To test this hypothesis, we performed stability analysis of high-density electrocorticography recordings covering an entire cerebral hemisphere in monkeys during reversible loss of consciousness. We show that, during loss of consciousness, the number of eigenmodes at the edge of instability decreases smoothly, independently of the type of anesthetic and specific features of brain activity. The eigenmodes drift back toward the unstable line during recovery of consciousness. Furthermore, we show that stability is an emergent phenomenon dependent on the correlations among activity in different cortical regions rather than signals taken in isolation. These findings support the conclusion that dynamics at the edge of instability are essential for maintaining consciousness and provide a novel and principled measure that distinguishes between the conscious and the unconscious brain. SIGNIFICANCE STATEMENT: What distinguishes brain activity during consciousness from that observed during unconsciousness? Answering this question has proven difficult because neither consciousness nor lack thereof have universal signatures in terms of most specific features of brain activity. For instance, different anesthetics induce different patterns of brain activity. We demonstrate that loss of consciousness is universally and reliably associated with stabilization of cortical dynamics regardless of the specific activity characteristics. To give an analogy, our analysis suggests that loss of consciousness is akin to depressing the damper pedal on the piano, which makes the sounds dissipate quicker regardless of the specific melody being played. This approach may prove useful in detecting consciousness on the basis of brain activity under anesthesia and other settings.
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Córtex Cerebral/fisiologia , Estado de Consciência/fisiologia , Inconsciência , Anestésicos/farmacologia , Animais , Córtex Cerebral/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Eletroencefalografia , Haplorrinos , Masculino , Processamento de Sinais Assistido por ComputadorRESUMO
Brain-wide interactions generating complex neural dynamics are considered crucial for emergent cognitive functions. However, the irreducible nature of nonlinear and high-dimensional dynamical interactions challenges conventional reductionist approaches. We introduce a model-free method, based on embedding theorems in nonlinear state-space reconstruction, that permits a simultaneous characterization of complexity in local dynamics, directed interactions between brain areas, and how the complexity is produced by the interactions. We demonstrate this method in large-scale electrophysiological recordings from awake and anesthetized monkeys. The cross-embedding method captures structured interaction underlying cortex-wide dynamics that may be missed by conventional correlation-based analysis, demonstrating a critical role of time-series analysis in characterizing brain state. The method reveals a consciousness-related hierarchy of cortical areas, where dynamical complexity increases along with cross-area information flow. These findings demonstrate the advantages of the cross-embedding method in deciphering large-scale and heterogeneous neuronal systems, suggesting a crucial contribution by sensory-frontoparietal interactions to the emergence of complex brain dynamics during consciousness.
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Encéfalo/fisiologia , Estado de Consciência/fisiologia , Vigília/fisiologia , Algoritmos , Animais , Biologia Computacional , Eletroencefalografia , MacacaRESUMO
BACKGROUND: Abnormal miRNA expression was recently implicated in the metastasis of oral squamous cell carcinoma (OSCC) and with a poor prognosis. The initiation of the invasion-metastasis cascade involves epithelial-mesenchymal transition (EMT). Our aim was to clarify how miRNA, especially miR-155-5p misexpression contributes to OSCC metastasis through EMT. METHODS: We collected tumor samples from 73 subjects with OSCC. The samples were analyzed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and correlations between miR-155-5p levels and clinical characteristics were investigated. OSCC cell lines were analyzed by miRNA microarray and by transfection with a miR-155-5p mimic or inhibitor, followed by proliferation and wound-healing migration assays. qRT-PCR analyses of EMT makers in cells transfected with miR-155-5p inhibitor were performed. RESULTS: We found high miR-155-5p expression in tissue samples from subjects with OSCC that had metastasized to cervical lymph nodes. HSC-3 cells also strongly expressed miR-155-5p. The epithelial marker E-cadherin was strongly expressed in HSC-3 cells transfected with miR-155-5p inhibitor, and we observed elevated SOCS1 and decreased STAT3 expression in these cells. CONCLUSIONS: Our results suggest that miR-155-5p causes OSCC to metastasize, and could serve as a novel therapeutic target for OSCC.
Assuntos
Carcinoma de Células Escamosas/genética , Neoplasias de Cabeça e Pescoço/genética , MicroRNAs/metabolismo , Neoplasias Bucais/genética , Antígenos CD , Biomarcadores Tumorais/genética , Caderinas/biossíntese , Caderinas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Transição Epitelial-Mesenquimal , Feminino , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Linfonodos , Metástase Linfática , Masculino , MicroRNAs/antagonistas & inibidores , MicroRNAs/biossíntese , MicroRNAs/genética , Pessoa de Meia-Idade , Neoplasias Bucais/metabolismo , Neoplasias Bucais/patologia , Metástase Neoplásica , Prognóstico , Fator de Transcrição STAT3/biossíntese , Fator de Transcrição STAT3/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço , Proteína 1 Supressora da Sinalização de Citocina/biossíntese , Proteína 1 Supressora da Sinalização de Citocina/genética , TransfecçãoRESUMO
Although the emerging field of functional connectomics relies increasingly on the analysis of spontaneous fMRI signal covariation to infer the spatial fingerprint of the brain's large-scale functional networks, the nature of the underlying neuro-electrical activity remains incompletely understood. In part, this lack in understanding owes to the invasiveness of electrophysiological acquisition, the difficulty in their simultaneous recording over large cortical areas, and the absence of fully established methods for unbiased extraction of network information from these data. Here, we demonstrate a novel, data-driven approach to analyze spontaneous signal variations in electrocorticographic (ECoG) recordings from nearly entire hemispheres of macaque monkeys. Based on both broadband analysis and analysis of specific frequency bands, the ECoG signals were found to co-vary in patterns that resembled the fMRI networks reported in previous studies. The extracted patterns were robust against changes in consciousness associated with sleep and anesthesia, despite profound changes in intrinsic characteristics of the raw signals, including their spectral signatures. These results suggest that the spatial organization of large-scale brain networks results from neural activity with a broadband spectral feature and is a core aspect of the brain's physiology that does not depend on the state of consciousness.